Julian Date Calculator

Julian dates (JD) serve as a continuous time system commonly employed in astronomy and related sciences to conveniently represent date and time as a single real number. Originating from Julian Day Number, the Julian date starts from noon Universal Time (UT) on January 1, 4713 BCE, as established in the Julian calendar. This tool converts between UTC (Coordinated Universal Time) and Julian dates.

You may download a reference calendar (pdf) from here: https://aavso.org/jd-calendar.